Knee Joint Aspiration and Injection THOMAS J

OFFICE PROCEDURES Knee Joint Aspiration and Injection THOMAS J. ZUBER, M.D., Saginaw Cooperative Hospital, Saginaw, Michigan Knee joint aspiration and injection are performed to aid in diagnosis and treatment of knee joint diseases. The knee joint is the most common and the easiest joint for the O A patient infor- physician to aspirate. One approach involves insertion of a needle 1 cm above and mation handout on knee joint aspiration 1 cm lateral to the superior lateral aspect of the patella at a 45-degree angle. Once the and injection is pro- 1 needle has been inserted 1 to 1 ⁄2 inches, aspiration aided by local compression is per- vided on page 1511. formed. Local corticosteroid injections can provide significant relief and often amelio- rate acute exacerbations of knee osteoarthritis associated with significant effusions. Office Procedures Among the indications for arthrocentesis are crystal-induced arthropathy, hemarthro- forms on knee joint aspiration and injec- sis, unexplained joint effusion, and symptomatic relief of a large effusion. Contraindi- tion are provided on cations include bacteremia, inaccessible joints, joint prosthesis, and overlying infection pages 1503, 1504 in the soft tissue. Large effusions can recur and may require repeat aspiration. Anti- and 1507. inflammatory medications may prove beneficial in reducing joint inflammation and fluid accumulations. (Am Fam Physician 2002;66:1497-500,1503-4,1507,1511-2. Copy- right© 2002 American Academy of Family Physicians.) This article is one in a nee joint aspiration and injec- when the effusion is small and the lateral series adapted from tion are performed to establish approach with larger effusions. The knee gen- the Academy Collec- a diagnosis, relieve discomfort, erally is easiest to aspirate when the patient is tion book Office Pro- cedures, written for drain off infected fluid, or supine and the knee is extended. family physicians, instill medication. Because Corticosteroids are believed to modify the designed to provide Kprompt treatment of a joint infection can pre- vascular inflammatory response to injury, the essential details of serve the joint integrity, any unexplained inhibit destructive enzymes, and restrict the commonly performed monarthritis should be considered for arthro- action of inflammatory cells. Intrasynovial in-office procedures, and published by Lip- centesis (Table 1). steroid administration is designed to maxi- pincott Williams & Arthrocentesis also may help distinguish mize local benefits and minimize systemic Wilkins. the inflammatory arthropathies from the adverse effects. Local corticosteroid injections crystal arthritides or osteoarthritis. If a can provide significant relief and often amelio- hemarthrosis is discovered after trauma, it can rate acute exacerbations of knee osteoarthritis indicate the presence of a fracture or other associated with significant effusions. anatomic disruption. There is no convincing evidence that corti- The knee is the most common and the eas- costeroids modify rheumatic joint destruc- iest joint for the physician to aspirate. It was tion, and steroid injections in patients with chosen for discussion here because of the fre- rheumatoid arthritis should be considered quent clinical problems associated with this ancillary to rest, physical therapy, nonsteroidal joint. The indications, complications, and pit- falls for knee arthrocentesis generally can be applied to other joints (Tables 2 and 3). Many TABLE 1 of the principles of needle aspiration and Indications for Arthrocentesis injection also can be used for soft tissue disor- ders, such as bursitis or tendinitis. Crystal-induced arthropathy An effusion of the knee often produces Hemarthrosis detectable suprapatellar or parapatellar Limiting joint damage from an infectious process swelling. Large effusions can produce ballotte- Symptomatic relief of a large effusion ment of the patella. Medial or lateral Unexplained joint effusion approaches to the knee can be selected; some Unexplained monarthritis investigators advocate the medial approach OCTOBER 15, 2002 / VOLUME 66, NUMBER 8 www.aafp.org/afp AMERICAN FAMILY PHYSICIAN 1497 TABLE 2 Contraindications to Intra-articular Injection Adjacent osteomyelitis Bacteremia Hemarthrosis Impending (scheduled within days) joint ϫ replacement surgery 1 inch of 4 4 gauze soaked with povi- Infectious arthritis done-iodine solution (Betadine) Joint prosthesis Hemostat (for stabilizing the needle when Osteochondral fracture exchanging the medication syringe for the Periarticular cellulitis aspiration syringe) Poorly controlled diabetes mellitus Sterile bandage Uncontrolled bleeding disorder or coagulopathy Procedure Description 1. The patient is supine on the table with the anti-inflammatory drugs (NSAIDs), or dis- knee extended (some physicians prefer that the ease-modifying antirheumatic drugs. knee be bent to 90 degrees). Some physicians Judicious use of corticosteroids rarely pro- prefer the medial approach for smaller effu- duces significant adverse effects. The intro- sions, but the lateral approach will be discussed duction of infection after injection is believed here. The knee is examined to determine the to occur in less than 1 in 10,000 procedures. amount of joint fluid present and to check for The concept of steroid arthropathy is largely overlying cellulitis or coexisting pathology in based on studies in subprimate animal mod- the joint or surrounding tissues. els, and it is an unusual occurrence in humans 2. The superior lateral aspect of the patella if the number of injections is limited to three is palpated. The skin is marked with a pen, one to four per year in weight-bearing joints. More fingerbreadth above and one fingerbreadth conservative researchers have even advocated lateral to this site. This location provides the limiting knee injections to three or four over most direct access to the synovium. an individual’s lifetime. 3. The skin is washed with povidone-iodine solution. The physician should be gloved, Methods and Materials although there is no consensus as to whether PATIENT PREPARATION sterile gloves must be used. A 21-gauge, 1-inch Clothing is removed from over the affected needle is attached to a 5- to 20-mL syringe, joint. The patient is placed in the supine posi- depending on the anticipated amount of fluid tion, and the knee is extended (some physicians present for removal. prefer to have the knee bent to 90 degrees). An 4. The needle is inserted through stretched absorbent pad is placed beneath the knee. skin. Some physicians administer lidocaine (Xylocaine) into the skin, but stretching the EQUIPMENT pain fibers in the skin with the nondominant Sterile Tray for the Procedure hand can also reduce needle-insertion dis- Place the following items on a sterile sheet comfort. The needle is directed at a 45-degree covering a Mayo stand: angle distally and 45 degrees into the knee, Sterile gloves tilted below the patella (Figure 1). Sterile fenestrated drape 5. Once the needle has been inserted 1 to 1 2 10-mL syringes 1 ⁄2 inches, aspiration is performed, and 2 21-gauge, 1-inch needles the syringe should fill with fluid. Using the nondominant hand to compress the opposite side of the joint or the patella may aid in Corticosteroids are believed to modify the vascular inflamma- arthrocentesis. 6. Once the syringe has filled, a hemostat can tory response to injury, inhibit destructive enzymes, and be placed on the hub of the needle. With the restrict the action of inflammatory cells. needle stabilized with the hemostat, the syringe can be disconnected and the fluid sent for stud- 1498 AMERICAN FAMILY PHYSICIAN www.aafp.org/afp VOLUME 66, NUMBER 8 / OCTOBER 15, 2002 Knee Aspiration TABLE 3 Contraindications to Joint Needle Aspiration Bacteremia Clinician unfamiliar with anatomy of or approach to the joint Inaccessible joints Joint prosthesis Overlying infection in the soft tissues Large, weight-bearing joints should not be injected with cor- Severe coagulopathy ticosteroids more than three to four times a year. Severe overlying dermatitis Uncooperative patient usually results from the needle coming into ies. Care should be taken not to touch the nee- contact with the highly innervated cartilaginous dle tip against the joint surfaces when removing surfaces. The needle can be redirected or with- the syringe. A syringe filled with corticosteroid drawn when pain is encountered. Slow, steady medication can then be attached to the needle. movement of the needle during insertion can 7. For injection, use betamethasone (Cele- prevent damage to the cartilage surface from the stone, 6 mg per mL), 1 mL, mixed with 3 to needle bevel. 5mL of 1 percent lidocaine.Alternately, methyl- • The Patient’s Effusion Was Sterile, But prednisolone (Depo-Medrol, 40 mg per mL), 1 Became Infected After the Joint Injection. Intro- mL, mixed with 3 to 5 mL of 1 percent lidocaine duction of infection into a joint is a rare event, can be used. After injection of the medication, occurring in less than 0.01 percent of injec- the needle and syringe are withdrawn. tions; however, infection can develop when the 8. The skin is cleansed, and a bandage is is needle is introduced into the joint through an applied over the needle-puncture site. The patient is warned to avoid forceful activity on the joint while it is anesthetized. Follow Up • After diagnostic arthrocentesis, appropri- ate intervention usually will be dictated by the results of the fluid analysis. Joint infections are usually treated aggressively with intra-

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